There is no denying that 2019 is off to a great start for Lady Gaga. Not only is she performing her best hits during her "Enigma" Las Vegas residency, but she's also out on the red carpet at award show after award show, thanks to the great success of A Star Is Born. Of course, one of the songs from the film, "Shallow," is also getting its due during awards season, so it may not come as a shock that Gaga has been playing it during her shows. Lady Gaga and Bradley Cooper's live "Shallow" duet in Las Vegas, though, arguably made her Saturday, Jan. 26 "Enigma" show even more memorable than any Little Monsters could have expected.

According to The Hollywood Reporter, Lady Gaga was getting set to play the hit song from the movie, but she had an idea to bring up a special guest from the crowd. That guest was none other than Cooper, of course. Clad in jeans, a black jacket, and a backwards baseball cap, Cooper came up on stage after Lady Gaga's call out to him. Once the pair reunited on stage, the fans could tell they were in for a treat, and they cheered on the duet, as Cooper took off his ball cap and got a little bit more into character as Jackson Maine.

Even if you haven't seen the film yet, you've likely heard "Shallow" at least a few times, so you can probably understand why the crowd was buzzing when Cooper and Gaga reunited on stage in Vegas to perform. And boy, did they deliver.

In the video posted to YouTube by Gaga Daily on Jan. 26, you can see Gaga set up Cooper with his "in-ears," which made him joke, "Jackson never used these," and then you can immediately tell that magic was about to happen. Watching the video of their performance, you can tell that they both pretty much transformed back into Jack and Ally for the duration of the song.

Cooper took the mic first for Jackson's opening lyrics, and Lady Gaga kneeled down by his feet with her hands folded, and it looked as if she was almost holding back tears in her eyes, with her gaze set on Cooper. And that was just beginning. I feel like I should give you fair warning right now that this whole video will definitely give you some ~feels~.

For Gaga's part, she took to the piano and played and sang with so much passion, as you would expect from the professional performer, but you could definitely tell she was channeling Ally as Cooper looked on from across the piano. They closed the song sitting next to each other on the piano bench, with Cooper's arm around Gaga's waist, and you could tell they had just given their all to the song. All in all, you guys, it was pretty much the best surprise performance any Lady Gaga fan could have asked for going into her show on Saturday, Jan. 26.

Gaga Daily on YouTube

A Star Is Born fans can also enjoy an extra dose of Cooper-Gaga loveliness on Sunday, Jan. 27, when both of them are slated to present at the Screen Actors Guild Awards. The film is also nominated for four awards on Sunday night, including both Cooper and Lady Gaga for Male Actor in a Leading Role and Female Actor in a Leading Role, respectively, so maybe a win during the night could lead to one more impromptu duet. Who knows? Whatever happens, fans will keep their eyes on the show, just in case. Until then, you can hold yourself over by watching this surprise Vegas duet on a loop.